Lasik, Lasek, Trans-PRK, Femtolasik
Lasik vs. Lasek
LASIK is a laser vision correction procedure that treats refractive errors, such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism (oval curvature), etc. by removing corneal tissue beneath the surface of the cornea.
During the LASIK procedure, a flap is created on the surface of the cornea. A computer-controlled excimer laser is then used to remove the proper amount of corneal tissue. In less than one minute, the excimer laser reshapes the internal cornea, or stroma. The thin flap of corneal tissue is then folded back into its original position, where it bonds after only a few minutes of drying.
On the other hand, no flap is created with LASEK surgery. Instead, the surgeon simply loosens the top layer of the cornea and moves it aside. After the laser has finished, this outer layer (the epithelium) is carefully placed back and left to heal over time.
FEMTOLASIK is a two step procedure involving two lasers. First, the surgeon creates a small flap in the cornea to prepare the eye for the next step, the vision correction.
The traditional LASIK method of laser vision correction requires a mechanical blade to make the flap.
However, in FEMTOLASIK method we create the flap using the FEMTO LDV™ femtosecond laser. It makes the whole procedure completely bladefree and enables the surgeon to tailor the procedure according to the very unique characteristics of every patient.
Transepithelial Photorefractive Keratectomy
Transepithelial photorefractive keratectomy (or Trans-PRK for short), represents a very recent iteration of laser refractive surgery. The evolution of this form of surgery started with PRK, which was soon overtaken by LASIK, or laser in situ keratomileusis. The reasons were that LASIK offered much faster recovery of vision and eye comfort than PRK, where recovery was delayed by the need for the surface cells of the cornea to heal. There is also less risk of corneal scarring and refractive regression with LASIK compared with PRK.
There remains a role for PRK, however, as LASIK involves the creation of a corneal flap. This weakens the cornea more than with PRK, where no flap is made. In patients with thinner corneas or where underlying weakness is suspected, PRK may be a safer option than LASIK.
Originally, during PRK the surface cells of the cornea were scraped off mechanically by a rotating brush, much like an electric toothbrush. Later, these cells were removed in a less traumatic manner by using alcohol to first loosen them, followed by gentle peeling off of the epithelial cells. This form of the surgery is still commonly performed in cases where PRK is chosen as the method of surgery. In order to avoid these extra steps required to remove the surface epithelial cells, a number of doctors and laser companies have attempted to use the excimer laser used to perform refractive surgery to also remove the cells. So far most of these lasers require multiple programming steps by the doctor and also require the doctor to use very subjective signs to tell when the epithelium is removed.
The Schwind Amaris 750S laser can now provide a one step, no touch, Trans-PRK surgery. Using the Trans-PRK mode, this laser first removes the surface epithelial cells with the excimer laser, and then proceeds immediately with the same laser to remodel the cornea for the refractive correction. Performing surgery in this manner allows all-laser PRK to be carried out in a very short time with minimal manipulation of the eye and in a very gentle way.
Evidence- Based Results of Trans-PRK Research Project
The Trans-PRK method is one of newest refractive surgical techniques by laser, which, for the first time in Iran, was used by Dr. Adib Moghadam employing the SCHWIND Laser Machine. Dr. Adib Moghadam, based on the latest evidence and scientific recommendation in this field, beside employment of years of research and experience, for each individual patient considers the demographic features (like age, sex) and optical characteristics (such as refractive conditions, intensity of refractive conditions, thickness of cornea, aberration, cornea surface, …) and individualize the surgical coordination. In other words, for planning the surgical procedure, a monograph is designed and used which could ascertain how to adapt the steps of procedure to the status of the patient. This leads to a better result of the surgery qualitatively and quantitatively.So that the German inventor of the Trans-PRK software for SCHWIND Laser Machine, Samuel Arba Mosquera, has acknowledged the way that Dr. Adib Moghaddam apply for Trans-PRK procedure is an improved and enhanced (Refined) model of which he has designed. The evidence of this issue is the recent survey on the results of Trans-PRK surgeries obtained by Dr. Adib Moghaddam and the eye clinic in Aschaffenburg / Germany. The results indicate that the outcomes of surgeries done by Dr. Adib Moghaddam are significantly better than the outcomes of German eye clinic in term of quantity of visual acuity and possible side effects of surgery.
One of the dominant factors in the monogram is aberration. Aberration in any optical system (as in the eyes) is defined as any distortion of the system performance from the ideal predicted status of the system by the physical-geometrical models. In eye optical system, this phenomenon can lead to disorders like hyperopia, shortsightedness, primary astigmatism, or more profound disorders such as vision distortion, corna, halo due to spherical aberration and alike conditions. Nowadays, the necessary technology for the assessment of patient’s aberration profile is available. The significance of this matter is due to the fact that assessment of this profile in each patient and considering it in procedure planning step lead to correction not only in the case of low degree aberration, but also in the cases of high order aberration. This fact is dominant in the quality of vision correction in each patient.
On the other hand, employment of laser surgery in the case of patients with hyperopia with astigmatism has been always controversial, since the success rate of the surgery and stability of vision status obtained in these patients, have not been as good as other patients.
Hyperopia patients: reviewing the follow-up data (even 3 years after surgery) from the cases of hyperopia that had undergone laser surgery by Dr. Adib Moghadam, revealed that the vast majority of patients had 100% or better vision. The finding suggests effectiveness of this technique and stability of the correction on this group of patients.
Patients with Astigmatism above 0.5: the performed analysis of the cases of patients with astigmatism (above 0.5) who undergone laser surgery by Dr. Adib Moghadam, after their follow-up (two years after surgery) suggests that over 95% of patients had 100% vision or better. The data claims that the surgical method is effective and provides a stable vision correction in this group of the patients.
By choosing Trans-PRK, usually epithelium requires less than 48 hours to repair. The patients gain a vision better than the standard vision, and it is also followed by more satisfactory from the patients. Analysis performed on the preoperative data and the data from follow-up sessions shows that in 6 months after surgery 95% of the patients had vision of 20/20 or better. Moreover in 6-month period after the surgery, the degree of the refractive disorder would be about 0.5 for 99% of the patients. All these results suggest high success rate and efficiency of the method.
Based on the analysis, the mean pain intenisty in 48 hours after surgery was marked in range of 0 to 2 in a 10-degree scale. This fact also states that the pain accompany the procedure is minimal. Furthermore, the risk of opacity and driness of cornea was also low, and the light irritatibility was also improved in the patients. Modification of cornea surface is not significant in these cases. Beside these, avoiding flap creation in this method, improve the symptoms involved with this procedure.
None of the patient who had had their surgery by Dr. Adib Moghadam claims Glare Flare after their surgeries.
The analysis of the patients‘ follow-up data show that 3 years after the surgery, over 95% of patients had 100% vision or better (many of these cases achieve the supervision). These data distinctivly states the stability of vision correction after surgery and no recurrence of the refractive condition.
This project has been carried out in hospital reseach centers with professional researchers involved. The results of this study have been presented in national and international conferences such as ESCRS, ASCRS, WOC, MEACO and AAO. Currently, there are more studies on-going with longer follow-up time to present the data in prestigious international journals. This study is embedded in an international clinical study of patients with Trans-PRK surgeries, with contribution from Valladolid University, Spain, and Augenklinik Aschaffenburg, Germany.
The researchers contributed to this study include: Dr. Farshad Nourizadeh, Dr. Mehdi Aslani, Dr. Amir Houshang Omidvari, Dr. Bahram Salmanian, Dr. Fatemeh Adili Moghadam, Dr. Saeed Soleimanjahi from Iran, and Dr. Samuel Arba Mosquera and Dr. Roberta Watter-Finke from Germany.
There is a list of recent international conferences that the successful results of the Trans-PRK surgeries done by Dr. Adib Moghaddam are presented for the world’s valid scientists and experts:
|Conference||Title of Presentation|
|American Academy of Ophthalmology (AAO), 2014||Brilliant results of this surgical technique for astigmatism|
|American Society of Cataract and Refractive Surgery (ASCRS), 2014||Brilliant results of this surgical technique for correction of hyperopia|
|European Society of Cataract and Refractive Surgery (ESCRS), Summer of 2014||Brilliant effects of this surgical technique on the visual quality|
|European Society of Cataract and Refractive Surgery (ESCRS), Winter of 2014||Brilliant results of this surgical technique for astigmatic patients with high numbers|
|International Society of Refractive Surgery (ISRS), 2013||Brilliant effects of this surgical technique for myopic patients with high numbers|
|European Society of Cataract and Refractive Surgery (ESCRS), 2013||Brilliant results of this surgical technique for myopic patients (1 year follow up)|
Research conducted by Dr. Adib Moghaddam, Dr. Adili, and Dr. Soleyman-jahi has been candidate for receiving the award from ESCRS, 2014. In this event, only a few cases selected from among hundreds of researches. After the final vote from judges, the prize winner is presented. For the first time, a research which is done in Iran is candidate to receive the award from the greatest European Society of Ophthalmology.